[2] Arhangel'skii A.V.: 
External bases in bicompacta. Soviet Math. Dokl. 1:3 (1960), 573-574. 
MR 0119188[3] Arhangel'skii A.V.: 
Mappings and spaces. Russian Math. Surveys 21:4 (1966), 115-162. 
MR 0227950[4] Arhangel'skii A.V., and Genedi H.M.M.: Beginnings of the theory of relative topological properties. pp.3-48 in: General Topology. Spaces and mappings, MGU, Moscow, 1989 (in Russian).
[5] Arhangel'skii A.V., Gordienko I.Ju.: 
On relative normality and relative symmetrizability. Moscow University Math. Bull. 50:3 (1995), 32-36. 
MR 1376351[6] Aull C.E.: 
Paracompact subsets. Proc. of the Second Prague Topological Symposium, pp.45-51, Prague, 1966. 
MR 0234420 | 
Zbl 0227.54015[8] Aull C.E.: 
Paracompact and countably paracompact subsets. Proc. of the Kanpur Topological Conference, pp.49-53, 1968. 
Zbl 0227.54015[9] Corson H.H., Michael E.: 
Metrization of certain countable unions. Illinois J. Math. 8 (1964), 351-360. 
MR 0170324[11] Nedev S.J.: 
$o$-metrizable spaces. Mosc. Math. Soc. Trans. 24 (1971), 213-247. 
MR 0367935